Vintage Tube amps

Tubes do tend to have a marvelous midrange, but not only midrange the whole thing top to bottom if you're listening to a good one. Tubes of course are obvious but in reality only a part of the equation. Transformers, caps, diodes and the overall design or topology all play important roles and contribute to the sound you hear. If it was rolled off at either end that was as likely transformers, or something to do with the amp and the speakers, and all the rest of the system as well.

Neither tube amps nor vintage amps are anything you can group into broad generalities like you are talking about. You really do have to take them just like everything else, one at a time.

There are great vintage tube amps that will give you plenty of the sound you are looking for. Especially if you are happy to use subs, that will allow you to use some high sensitivity speakers without having to worry about bass, you can focus on midrange and up, should be plenty of candidates to choose from. A modded/upgraded ST70 probably would fit the bill. But there are plenty of others.

Depending on your budget and timeline, I just ordered a Raven Blackhawk and will be listing my Melody when the Raven is ready in a month or so. https://systems.audiogon.com/systems/8367 Something like this will definitely perform like you are looking for.

Obviously, most tube amps are not like that, but the sound of any amp is affected by the impedance curve of the speakers it is driving.

A high output impedance tube amp + a speaker with a low and falling impedance in the high frequencies will sound rolled-off! Conversely a speaker with a rising impedance in the bass frequencies will sound excessively heavy! 

Tube amps with output impedance of 1 ohm and higher will act like "tone controls" as they track speakers' impedance curves! 

Most of the best systems I’ve heard had tube amps....some old, some new. How they sound depends on a ton of variables, but the sound on all of them can be tailored a bit by the tube choices. At their best, tube amps offer great frequency response, and a holographic image.

Every audiophile should be required to listen to a vintage Dynaco ST70 with quality tubes.  

It will provide the floor for how good a low cost tube amplifier can sound.

- Zu speakers at 97db may not quite be efficient enough for your 2wpc amp ( 45 tubes?). depending on the dynamics and listening level you desire of course. But you are supplementing with a sub so do you have a filter to roll off the bass to the main speakers?

- Dynaco ST 70's / Mk4 monos, etc. all have slightly rolled off top end from my experience with them. And yes mine are heavily modified. So I'd not recommend them if your missing the top end already. 

- The Fisher tube amps are a better step up the vintage tube amp arena (look for an old console stereo amps they are quite good and don't have all the preamp stuff).

- Luxman tube stuff is great too ( if not going up to silly money in the used market),  many others out there form the early Audio Research stuff, some select Mac's and even HH Scott gear can be really good after a rebuild. There's many choices out there just need to do some research as not everything from a specific manufacturer is great when it comes to vintage.

- SET, parallel SET, Push Pull etc many topologies all can be really good if implemented well. 

- read about tube types and their associated sound signatures and pick an amp that have the tubes you like. 

Also  with vintage you need to consider most will require service with most likely a recap and some specific replacement parts that are known to fail or drift out of spec. So When I buy vintage gear I always add in to the cost a service call and a complete re-tube as everyone lies about tube age, ok not everyone but you get the idea you cant rely on them to be good. 

Vintage gear has also gone crazy in the used market with COVID and IMO its not a good time to buy vintage right now, its a sellers market for sure. Unless you've found a holly grail of cheep gear. 

I think many of us have memories like you describe. Deeply emotional warm, beautiful… and without top or bottom. I have some that really stick. I now have an all tube system with outstanding top and bottom. One product, I think it is the Audio Research VT80se… part of their foundation series really got the incredible midrange bloom right as well as top and bottom and 75 Watts per channel. So you can get both in a modern system. 

Hey @millercarbon, you might hang on to your Melody as a backup amp, non?

No reason to assume tube amps roll off the highs.

My rebuilt Mac MC40 monoblocks are awesome and not rolled off at all. Best audio investment I ever made.
BillWojo